• Title, Summary, Keyword: 50% Volumetric Diameter

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윤활유 첨가제에 따른 마멸분 화상해석

  • 서영백;이충엽;박홍식;전태옥
    • Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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    • pp.180-189
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    • 1998
  • This paper was undertaken to do shape analysis of wear debris on oiliness agent and extreme pressure agent. The lubricating wear test was performed under different experimental conditions using the wear test device was made in our laboratory and were- specimens of the pin on disk type was rubbed in paraffine series base oil by materials, varying applied load, sliding distance, oil additives such as stearine acid, DBDS, TCP. The four shape parameters (50% volumetric diameter, aspect, roundness and reflectivity) on a kind of the additives are different on applied load and sliding distance and Its are affected by absorbed film and reaction film. DBDS and TCP have a role of extreme pressure agent but a role of absorbed film of stearic acid decrease in high load. The maximum wear volume on applied load be in existence in three kinds of the specimens because of reaction characteristics of the additives.

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Condition Monitoring of Hydraulic Piston Motor using Morphological Analysis of Wear Particles (마멸입자 형태해석에 의한 유압피스톤용 모터의 상태감시)

  • 문병주;조연상;박흥식;전태옥
    • Journal of The Korean Society of Manufacturing Technology Engineers
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    • v.9 no.6
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    • pp.127-132
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    • 2000
  • Morphological analysis of wear particles is one of useful methods for machine condition monitoring because it is well reflected in machine driving state. This paper was undertaken to apply to the condition monitoring of hydraulic piston motor. The lubricating wear test was performed under different experimental conditions using the wear test device and wear specimens of the pin on disk type was rubbed in paraffinic base oil by three kinds of lubricating materials, varying applied load, sliding distance. The four shape parameters(50% volumetric diameter, aspect, roundness and reflectivity) are used for morphological analysis of wear particles. The results showed that the four shape parameters of wear particles depend on a kind of the lubricating materials. It was capable of calculating presumed wear volume for three kinds of materials on driving time to foresee as damage condition of lubricating materials.

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Presumption of Slipper-pad Fault Condition for Hydraulic Rotary Actuator (마멸입자 해석을 통한 유압로터용 Slipper - Pad의 손상상태 추정)

  • 전성재;조연상;서영백;박흥식
    • Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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    • pp.62-67
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    • 2000
  • This paper was undertaken to do morphological analysis of wear debris for slipper-Pad of hydraulic rotary acuator. The lubricating wear test was performed under different experimental conditions using the wear test device and wear specimens of the pin on disk type was rubbed in paraffinic base oil by three kinds of lubricating materials, varying applied load, sliding distance. The four shape parameters(50% volumetric diameter, aspect, roundness and reflectivity) are used for morphological analysis of wear debris. The results showed that the four shape parameters of wear debris depend on a kind of the lubricating condition. It was capable of presuming wear volume for slipper-pad of hydraulic rotary acuator on driving time.

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Applicaion of Neural Network for Machine Condition Monitoring and Fault Diagnosis (기계구동계의 손상상태 모니터링을 위한 신경회로망의 적용)

  • 박흥식;서영백;조연상
    • Tribology and Lubricants
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    • v.14 no.3
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    • pp.74-80
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    • 1998
  • The morphologies of the wear particles are directly indicative of wear process occuring in the machine. The analysis of wear particle morphology can therefore provide very early detection of a fault and can also ofen facilitate a dignosis. For this work, the neural network was applied to identify friction coefficient through four shape parameters (50% volumetric diameter, aspect, roundness and reflectivity) of wear debris generated from the machine. The averages of these parameters were used as inputs to the network. It is shown that collect identification of friction coefficient depends on the ranges of these shape parameters learned. The various kinds of the wear debris had a different pattern characteristics and recognized relation between the friction condition and materials very well by neural network. We discuss how the network determines difference in wear debris feature, and this approach can be applied for machine condition monitoring and fault diagnosis.

Forceseeability and Decision for Moving Condition of the Machine Driving System by Artificial Neural Network (인공신경망에 의한 기계구동계의 작동상태 예지 및 판정)

  • Park, H. S.;Seo, Y. B.;Lee, C. Y.;Cho, Y. S.
    • Journal of The Korean Society of Manufacturing Technology Engineers
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    • v.7 no.5
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    • pp.92-97
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    • 1998
  • The morpholgies of the wear particles are directly indicative of wear processes occuring in machinery and their severity. The neural network was applied to identify wear debris generated from the machine driving system. The four parameters(50% volumetric diameter, aspect, roundness and reflectivity) of wear debris are used as inputs to the network and learned the friction condition of five values(material 3, applied load 1, sliding distance 1). It is shown that identification results depend on the ranges of these shape parameters learned. The three kinds of the wear debris had a different patter characteristic and recognized the friction condition and materials very well by artificial neural network. We discussed how the network determines differencee in wear debris feature, and this approach can be applied to foreseeability and decisio for moving condition of the Machine driving system.

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Performance of Evaporation Heat Transfer Enhancement and Pressure Drop for Liquid Nitrogen (액체질소에 대한 증발 열전달 촉진 및 압력강하 성능)

  • Nam, Sang-Chul;Lee, Sang-Chun;Park, Byung-Duck
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.24 no.3
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    • pp.363-372
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    • 2000
  • An experiment was carried out to evaluate the heat transfer enhancement and the pressure drop characteristics for liquid nitrogen using wire-coil-insert technique under horizontal two-phase conditions. The tube inner diameters were 8 mm and 15 mm, respectively and the tube length was 4.7 m. The helix angle of the wire coil insert was $50^{\circ}$ and its length was 4.7 m. Heat transfer coefficients for both the plain and the enhanced test tubes were calculated from the measurements of temperatures, flow rates and pressure drops. A correlation in a power-law relationship of the Nusselt number, Reynolds number and Prandtl number for the heat transfer was proposed which can be available for design of cryogenic heat exchangers. The correlation showed that heat transfer coefficients for the wire-coil inserts were much higher than those for plain tubes, increased by more than $1.8{\sim}2.0$ times depending upon the range of the equivalent Reynolds number. The correlation was compared with other various correlations in the turbulent flow conditions.

Morphological Analysis of Wear Particles in the Lubricating Oil with Additives (유성제 및 극압 첨가제에 따른 마멸입자 형상해석)

  • 이충엽;조연상;서영백;박흥식;전태옥
    • Tribology and Lubricants
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    • v.14 no.4
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    • pp.79-87
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    • 1998
  • Morphological analysis of wear particles in the lubricating oil is a very effective and versatile means of lubricant analysis for machine condition monitoring and fault diagnosis. The prospects for determining quantitative information about wear particle morphology have been considerably enhanced by recent developments reported in the application of image processing and analysis techniques. This study was undertaken to investigate the influence of oiliness agent and extreme pressure agent on the shape of wear particles. The wear test was performed under different experimental conditions with stearic acid, dibenzyl disulfide(DBDS) and tricresol phosphate(TCP) in paraffinic base oil. Wear particles characteristics were described using four shape parameters, namely 50% volumetric diameter, aspect, roundness and reflectivity. The results showed that the four shape parameters of wear particles depend on a kind of the additives. This analysis of wear debris with computer image processing techniques is sufficient to distinguish some types of wear debris. The wear volume of three kinds of the specimens are affected by the additives with boundary films.

Decision of Friction Condition for Materials of Automobile Transmission by Theory of Intelligence (지능이론을 이용한 자동차 트랜스미션 소재의 마찰조건 판정)

  • Cho Yonsang;Kim Younghee;Park Heungsik
    • Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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    • pp.312-315
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    • 2004
  • A lubricated state of an automobile transmission can not be inspected directly with eyes. Thus, it needs to develop a more general method. Wear debris can be collected from the lubricants of operating transmission of an automobile and its morphology is directly related to the fiction condition of the interacting materials from which the wear particles originated in lubricated transmission. In this paper, to identify the friction condition for transmission gear by neural network, the wear test of ball-on-disk type and the analysis of friction state were carried out for carburized SCM420 and nitrocarburized NT100 under different experimental conditions. The four shape parameters($50\%$ volumetric diameter, aspect, roundness and reflectivity) of wear debris were calculated by the image processing system. They were used as input values to identify the moving condition of transmission gear by the neural network.

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Numerical analysis for deformation characteristics under the freezing and bursting of Al pipe (알루미늄 관의 동파 거동특성에 관한 수치적 연구)

  • Choi, Seung-Hyun;Lee, Dong-Won;Ko, Young-Bae
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.15 no.8
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    • pp.4763-4768
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    • 2014
  • Recently, aluminum pipes have been used instead of steel pipes for open and shut machines in vinyl housing because of its corrosion-resistance and light weight. In particular, the light weight is very useful for fitting and removal by human resources. On the other hand, an aluminum pipe is weak in winter because aluminum has a larger thermal expansion coefficient than steel. This study examined the freezing and bursting of aluminum pipes by numerical analysis. The mechanical-thermal deformation characteristics were analyzed under the condition of ice volumetric expansion in aluminum pipes reaching 50%. From numerical analysis, large stresses above the yield stress occurred in aluminum pipe after ice expanded in the net diameter immediately. In addition, the freezing and bursting of aluminum pipes was predicted around an ice volumetric expansion of 6 - 7% because the thickness of the aluminum pipe reached an aluminum elongation ratio of 17%. Therefore, it is recommended that aluminum pipes be sealed perfectly to prevent water flow in the pipe. These results suggest that it is very difficult to prevent freezing and bursting of aluminum pipes by water freezing in the pipe.

Effect of Testosterone Administration on the Spermatogenesis in Rats (Testosterone의 투여(投與)가 흰쥐의 조정기능(造精機能)에 미치는 영향(影響))

  • Lee, Kyu Seung
    • Korean Journal of Agricultural Science
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    • v.2 no.2
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    • pp.405-413
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    • 1975
  • The objective of this study was to examine the effect of testosterone on the spermatogenesis. Testosterone propionate was administered in 20 mg dose to male rat with 10 days interval for 50 days and the treated rat was compared with normal one in their testis weight and histological changes. The results were as follows: 1. The longer treatment gave the more decreased testis weight. Treated rat for more than 20 days was significantly different from the untreated one. 2. Diameter of seminiferous tubule was significantly reduced in 40 and 50 days treatments. 3. The ratio of disrupted spermatogenesis on seminiferous tubles was significantly increased from 20 days treatment. 4. On volumetric proportion of testicular structure, spermatozoa and spermatid were significantly reduced from 20 and 30 days treatments respectively. Other components in testis were not changed. 5. The administration of testosterone in over dose damages spermatozoa and spermatid more than other components in testis.

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